Have you looked at the other Forms plugin called WikiForms? I started using TracForms originally and switched to WikiForms because there seemed to be more flexibility there (additional field types besides check boxes, user-definable permissions on fields, etc) and TracForms development had slowed at that time.
However, since then, development on WikiForms seems to have slowed and development on TracForms seems to have picked up. The functionality that I need is the ability to use permissions to limit parts of forms to specific user groups. Also, the ability for the form to trigger an external event or condition would make the forms more usable for me.